The Doctor might be my favorite Voyager character. It's one of those things that sort of wavers day by day. But, through all these years, each time I watch the series, as much as I love Janeway, Seven, B'Elanna, and Neelix, I tend to keep coming back to The Doctor. I love the way his character develops, I love the way he's played, and I love the episodes that were written for him. He's Voyager's Spock/Data/Odo. He spends seven seasons exploring his humanity, trying to better understand what it means to be a person, what it means to create and develop relationships and, occasionally, what it means to fall in and out of love.
In Heroes and Demons he saves the day but not the girl. Freya, a badass viking maiden goes to her untimely death after bestowing a kiss on The Doctor. His first kiss. It's a holodeck kiss but it's not without meaning. My first kiss was similar. I was in Romeo and Juliet when I was fifteen and I'd never kissed anyone. I still remember standing in the rehearsal hall with my Romeo, in the middle of the summer, sweating through my Sailor Moon t-shirt and leaning in for my first kiss only to bump teeth in front of all the Montagues and Capulets. It might not have been a kiss borne out of love (even puppy love) but and thus not "real" but, in spite of the falseness of the situation, it still meant something to me.
The Doctor's relationships move into the (sort of) real world in Lifesigns wherein a Vidian scientist (infected with the Phage) shows up in sick bay. After transferring her mind (temporarily) to a non-infected body, they work together to treat her injuries and dysfunctional braincells. They become closer as the days pass and, eventually, their friendship builds into a romance. Eventually, The Doctor goes to Tom Paris for advice and ends up parking in a 57 Chevy on Mars with his lady friend:
This episode is beautiful and quiet in its exploration of The Doctor's character, his first real romance, and his newfound ability to truly fall in love. Watch it.